Well known methods exist for making polarizing glass. One such commercial method is by reducing silver or lead ions in a glass to the atomic state. For certain recent applications it has become desirable to provide glass having both polarizing and non-polarizing regions integral thereto. While methods have been known for many decades for making polarizing glass, until recently, it had not been widely known that polarizing and non-polarizing glass regions can be made integral to a single glass surface. Two such techniques have recently been disclosed in copending, co-assigned U.S. application Ser. Nos. PCT/US 97/04870 and 60/044,790 (both herein incorporated by reference), which have suggested different approaches for forming polarizing regions in non-polarizing glass by photolithographic methods as well as by ion-exchange methods.
The above recent techniques notwithstanding, there continues to be a need for simpler and improved methods of producing polarizing/non-polarizing glass. Accordingly, it is the object of this invention to provide a new and improved method for making polarizing glass regions in non-polarizing glass.